Exotic Pumpkinseed Sunfish Lepomis gibbosus (Linnaeus, 1758) in the International Minho River (Iberian Peninsula), and Parasitic Association with Myzobdella lugubris Leidy, 1851 (Annelida, Hirudinea)

Abstract

To evaluate the establishment of the emerged species Lepomis gibbosus (Linnaeus, 1758) in the international section of the Minho River (Iberian Peninsula) the abundance was analysed for 7 years. This study also describes the world’s first record of parasitism between the leech Myzobdella lugubris Leidy, 1851 and L. gibbosus. The earliest record of species L. gibbosus , also known as pumpkinseed sunfish, was in the Spanish area of the Minho River basin, in the beginning of the 2000s. It is considered an established species in the estuary, due to its ecological release capacity, which has been increasing over the last few years. Physical condition, age, feeding patterns, and reproduction habits were analysed from July 2014 to October 2015. Individuals sampled appear in a good physical condition (b>3). The oldest individual captured was 4 years old, with L max =18.6cm. Females have a higher gonadosomatic investment than males (F 1;585 =150.43, p<0.01), particularly in July (F=7.39%; M=1.4%), which comply with the values of the hepatosomatic index (F 2;300 =34.23, p<0.01). Breeding season occurs between July/August and sexual maturity is reached at age of 1. Regarding the feeding regime, 18 taxa were identified from gut content. In the first year of life, the pumpkinseed has a preference for insects and crustaceans. In adult age, gastropods are the preference, which can cause trophic competition with native species. Therefore, monitoring studies should continue to follow the population dynamics.